1. Field of the Invention
The present invention relates to a mechanism for inserting and guiding an flexible endoscopic tube provided with a sensor, such as a photographing element, to a target position in a human body cavity, and particularly to a mechanism for horizontally and vertically controlling a part of the flexible tube.
2. Description of the Prior Art
The flexible tube employed in an endoscope has a sensor at its head end, which is inserted into a body cavity, to observe, diagnose and treat the target area.
Since the human body cavity has complex curves, the flexible tube is bent along these curves of the body cavity by the operator's manipulation. To achieve this, at the head portion of the flexible tube, an articulated pipe is provided, composed of cylindrical articular chips joined in series with joint pins. This articulated pipe enables the flexible tube to be inserted along the human body cavity.
The articular chips are preferably made of metals, and joint pins for joining the articular chips, for example, rivets made of stainless steel. A metal has disadvantages in that it has a high friction factor and is easily abraded and corroded.
A desirable material for articular chips might be ceramics having a low friction factor. Toughness of the ceramics, however, is inferior to that of metals, so that, when the ceramic articular chips are joined together by hitting the joint pins with a hammer to deform for complete coupling of the articular chips, the ceramic articular chips may be easily damaged.